Jan. 22-25

This week, I learned about the concepts of Dalton's theory.

Dalton's Playhouse Visual Learning

On Monday, I did a simulation on Dalton's theory in the computer game. The first part of the game consisted of burning the calx (Priestley). As 7.39g of the 100g calx was burned, only 92.61g remained. This time, I tried 200g of calx. Using my understanding of the Law of Conservation of Mass, I predicted that twice the amount of mass from the first trial would burn. It turns out that this was true. The change in mass was 14.78g was subtracted from the 200g calx. Therefore, depending on the mass of a substance burning, it loses mass at a proportional when comparing it to the same substance with a different mass.

However, I considered this: What about the volume of gas that was in the experiment? Well, I figured that the more mass was burned, the more volume the calx would be surrounded in since mass and volume have an indirect relationship. Using the 100g, the volume of gas came out to be 5.171L, and then using the 200g, the volume of gas came out to be 10.34L. Therefore, since there is only half of the mass of calx left, the volume doubled. Also, the volume of gas changed at a proportional rate to the rate at which the mass of calx changed.

So, this then establishes a core Dalton principle: Chemical reactions occur at a proportional rate. This is indeed true as everything else (mass, volume, etc.) change at that same proportional rate.

The next experiment I did in this activity was the Lavoisier stage. This is where the phlogiston and the oxygen were tested at burned at different rates to see how they would change in mass or volume. First, 1/3 of the phlogiston was burned. To begin with, both started out with volumes of 6L and they were both in separate beakers , which had tubes connecting to a center beaker, which is where the gas would go. As the oxygen and phlogiston burned, 5L for both were left.

Next, as 2/3 of the phlogiston were burned, 4 L for both oxygen and phlogiston were left.

So far, one could extrapolate that they would change at the same rate based on the results of these two trials. However, when all the phlogiston was burned, only half of the oxygen was consumed so that 3L of oxygen were left.

Therefore, this concludes that phlogiston burned at a quicker rate than oxygen. But how? And why? I speculate that it has to do with the fact that phlogiston was more flammable, therefore, it would burn at a quicker rate. Then, as soon as I realized that phlogiston was renamed hydrogen, I then thought, "Of course!" And I then thought of the Hindenburg incident where it blew up because the hydrogen that it was filled with was flammable, and so when it came in contact with the flame (presumably from an explosion), the Hindenburg exploded. Therefore, I think that hydrogen is flammable possibly because it may be just able to bond with almost any element since it makes just one bond (hence, any element can make one or more bonds). Overall, hydrogen burned twice as fast as the oxygen in the Dalton simulation.

Both consist of a similar chemical composition and consist
of carbon. Therefore, they change mass and volume at
the same rate and number during a chemical reaction.

Lastly, I worked on the Diamond and Charcoal lab. I started out with 0.20g of charcoal and diamond and kept the mass of oxygen at 1.06g and volume at 0.74L constant (charcoal and diamond were tested individually). The mass of the oxygen decreased from 1.06g to 0.73g as the subtracted amount went to the 0.20g of charcoal, thus increasing the mass of charcoal to 0.53g. Next, 0.40g of charcoal was tested with the same volume of gas (0.74L). Then, the mass of gas dropped from 1.06g to 0g and the volume dropped from 0.74L to 0L. Therefore, with twice the mass, the rate at which volume dropped doubled, hence the rate at which charcoal's mass increased. Hence, chemical reactions occur at a proportional rate and inversely affect each other, and subtracted amount is added somewhere else in a closed system.

Then, 0.20g and 0.40g of diamond were tested. The results were the same. Thus, charcoal and diamond have similar chemical properties (e.g. melting point, boiling point, etc.) so that they can change at the same rate and may consist of the same kind of elements (carbon, for example).

From this lab, I learned that chemical reactions occur at the same rate, whether they are in a closed or open system. I learned that the amount of mass in a closed system would stay the same while in an open system, the total mass of the reactants won't come out of the system. Based on this, volume could be affected as well. If the mass left the system, then the volume would increase. But, if it is in a closed system, the total volume won't change.